Laterally emitting optical waveguide and method for introducing micromodifications into an optical waveguide

Abstract

The present invention relates to an optical waveguide comprising an optical waveguide core, a region of the optical waveguide, wherein micromodifications are arranged in the region of the optical waveguide.

Description

[0001] The invention relates to an optical waveguide and a method for introducing micromodifications into an optical waveguide.

[0002] Optical fibers known in the prior art generally consist of an optical fiber core (hereinafter referred to as the core) and an optical fiber cladding (hereinafter referred to as the cladding). Quartz glass is a commonly used manufacturing material, but is not limited to it. To ensure loss-free light guidance within the core, the refractive index of the cladding is lower than that of the core. This allows total internal reflection to be utilized at the transition between the core and the cladding, thus guiding the light within the core of the optical fiber. Sometimes the cladding is coated with an additional cladding.Conventional optical fibers often also have a so-called coating and / or a buffer, which can surround the cladding. These additional layers are usually designed in such a way that they serve the mechanical stability of the optical fiber in general and in particular ensure the non-destructive flexibility of the optical fiber and the mechanical protection of the optical fiber against external influences.

[0003] Typically, the light coupled into the core on one side is continued within the core with virtually no loss and then coupled out of the optical fiber at the other end. In order to change the light path of the light within the core, it is known to introduce modifications into the material of the core or into the edge region between the core and cladding. By diffraction and / or scattering and / or refraction of the light at these modifications, which can be described as disturbances, the light path can be changed in such a way that a targeted lateral coupling out of at least portions of the light guided in the core of the optical fiber can be achieved. If the modifications have been introduced over a defined distance along the core and / or the edge region between the core and cladding, the lateral coupling out can also occur over this defined distance.

[0004] The areas treated in this way can serve as so-called fiber applicators, which are usually located at one end of the optical fiber or in between. It is also known to realize these so-called fiber applicators essentially using attachments attached from the outside. For example, watertight attachments are known which are attached to one end of the optical fiber. To change the light path and couple the light out laterally, either the mechanically and / or chemically roughened end of the optical fiber or a liquid mixed with scattering particles, which circulates in the liquid-tight attachments, is used. Applicators of this type are known, for example, from the documents DE 41 37 983 C2, DE 42 11 526 A1 or DE 43 16 176 A1.

[0005] Another design of such a mounted applicator, as known, for example, from DE 101 29 029 A1, US Pat. No. 4,660,925, or US Pat. No. 5,196,005, is a hollow body attachment that is attached to one end of the optical fiber. The hollow body is filled with a carrier matrix, e.g., a silicone gel, into which the particles serving as scattering centers are incorporated. The concentration of the scattering particles can be homogeneously distributed or increase sequentially toward the end.

[0006] Such attached fiber applicators are usually made of polymer materials and are therefore very elastic and mechanically resilient. However, they also have significant disadvantages, which are essentially due to the two-part design of the optical fiber and attached applicator. For example, the thermal resilience of attached applicators is usually significantly lower than that of the optical fiber. There is also a risk of such applicators becoming detached from the optical fiber. Different manufacturers of such attached applicators typically use different materials, which results in different thermal and mechanical properties of the applicators, making them suitable only for specific wavelengths and power levels. This makes switching between different applicators significantly more difficult, especially since these fiber applicators are optimized for specific applications.Another critical disadvantage of attached applicators lies in the manufacturing process. Assembly is typically performed manually and, due to its complexity, is not automated. Furthermore, bubbles or foreign matter can be trapped during production, causing disproportionate light refraction and creating unwanted hotspots, resulting in a relatively high reject rate.

[0007] DE 44 07 547 A1 describes a method for introducing modifications into transparent materials using focused laser radiation. Laser pulses in the nanosecond range are used to generate microcracks within the transparent material, which can serve as light scattering centers. These microcracks thus generated pose a problem when transferring this method to applications in optical fibers. These cracks would lead to such material weakening within an optical fiber that, under thermal or mechanical stress, e.g., bending of the optical fiber, the optical fiber could damage or even break it. Furthermore, the size and orientation of these microcracks relative to the optical fiber axis cannot be controlled.

[0008] DE 197 39 456A1 describes a method for introducing micromodifications into an optical fiber that serve as scattering centers. The processing parameters, such as the pulse duration of the laser radiation used, are not described in detail, so the exact nature of the resulting micromodifications is uncertain. However, the precise shape has a decisive influence on the radiation and mechanical stability of the optical fiber.

[0009] Likewise, EP1342487 B1 discloses a laser applicator comprising an optical waveguide with scattering means suitable for scattering the light guided inside, at least partially, out of the core of the optical waveguide, with at least some of the scattering centers forming a diffraction grating. While methods suitable for introducing the scattering centers into the interior of the optical waveguide are described, the precise setting of the parameters necessary to specifically control the characteristics of the scattering centers is not described.

[0010] WO 2004 / 005982 A2 describes a method for microstructuring optical fibers using ultrashort laser pulses. This and the other methods mentioned above are formulated in general terms and contain information on the shape, size, and distribution / arrangement of the generated microstructures without addressing any specific design with regard to thermal and mechanical stability, both with regard to the microstructures and the processed optical fibers.

[0011] It is known that when the optical fiber is bent or subjected to other stresses (e.g. mechanical and / or thermal), mechanical failure (breakage of the optical fiber) can occur if the stresses occurring inside the optical fiber have an excessive impact on its mechanical stability. Microcracks can occur in the outer region of the optical fiber cladding as early as during the manufacturing process, particularly during the drawing process. The resulting stresses can be dissipated via the mechanical connection between the coating (and / or the buffer) and the surface of the cladding, so that there is no amplification (so-called crack propagation) and thus no impairment of the mechanical stability of the optical fiber. It is also a known problem that any further processing of the interior of the optical fiber, e.g. of the core or the cladding, impairs the mechanical stability of the optical fiber.As a result, stresses that an unprocessed optical fiber can still tolerate can lead to crack propagation in a processed optical fiber, which can lead to the optical fiber breaking.

[0012] The object of the invention is to avoid or mitigate one or more disadvantages of the prior art. In particular, the object of the invention is to provide an optical waveguide that is suitable for laterally radiating at least portions of the light guided within it and, at the same time, has the highest possible mechanical stability. It is also an object of the invention to provide a method for introducing micromodifications into an optical waveguide that are suitable for laterally radiating at least portions of the light guided within the optical waveguide.

[0013] The object is achieved starting from an optical waveguide according to the preamble of claim 1 by the features specified in the characterizing part of claim 1, as well as by the features of the method for introducing micromodifications named in claim 11.

[0014] The optical waveguide according to the invention comprises a light-guiding core and a region at the distal end of the optical waveguide, wherein micromodifications are arranged in the region in the distal end of the optical waveguide, the arrangement of the micromodifications being orderly. In contrast to a disordered or chaotic distribution, an ordered distribution of the micromodifications makes it possible to control the stress distribution and the radiation geometry in the optical waveguide. With a disordered distribution, it could happen that additional micromodifications are placed precisely in the area of ​​stress peaks, further increasing the stress. This then inevitably leads to further mechanical weakening in this area, which can cause damage to the optical waveguide. If the micromodifications are introduced in an orderly manner, the stress distribution can be actively controlled.This makes it possible to distribute the mechanical stress through the micromodifications in such a way that, compared to optical fibers with a chaotic distribution of micromodifications, higher mechanical stresses can be introduced during operation before the optical fiber fails. Furthermore, a targeted arrangement of the micromodifications can reduce processing time, as micromodifications are only introduced where they meaningfully contribute to the lateral emission of the light guided in the optical fiber. This cannot be guaranteed with a random distribution of the micromodifications. Therefore, with a random distribution of the micromodifications, more micromodifications must be introduced to achieve the same laterally emitted intensity than with an ordered arrangement of the micromodifications.

[0015] In a preferred embodiment of the optical waveguide, the micromodifications are arranged on one or more parallel sectional planes, wherein the first sectional plane is perpendicular to the optical waveguide axis, and wherein the arrangement of the micromodifications on the first sectional plane is defined by one or more parameters from a group of parameters comprising the symmetrical arrangement of the micromodifications, the density of the micromodifications on the first sectional plane, the density of the micromodifications, the size of the micromodifications, the distance of the micromodifications from the optical waveguide axis, the distance of the micromodifications from one another, the orientation of the micromodifications or other parameters with the aid of which the position and distribution of the micromodifications or their size or external shape is described.

[0016] In a further preferred embodiment of the optical waveguide, the arrangement of the micromodifications on a first cutting plane is repeated on at least one other cutting plane. This has the advantage that processing routines can be repeated and a stress distribution created by a specific arrangement of micromodifications can be continued over a longer area.

[0017] In a further particularly preferred embodiment of the optical waveguide, the at least one other cutting plane on which the arrangement of the micromodifications on the first cutting plane is repeated is rotated by an angle relative to the first cutting plane.

[0018] In a further particularly preferred embodiment of the optical waveguide, the distance between the first cutting plane and at least one other cutting plane on which the arrangement of the micromodifications is repeated is greater than the extent of a single micromodification.

[0019] In a further embodiment of the invention, the distance between the first cutting plane and the at least one other cutting plane on which the arrangement of the micromodifications is repeated is less than the extent of a micromodification in the axial direction of the optical waveguide, as long as the micromodifications do not overlap or obstruct the beam passage.

[0020] In a further particularly preferred embodiment of the optical waveguide, between the first cutting plane and the at least one other cutting plane on which the arrangement of the micromodifications of the first cutting plane is repeated, there is at least one further cutting plane with micromodifications which has a different arrangement than the first cutting plane,

[0021] In a further particularly preferred embodiment of the optical waveguide, the micromodifications on the first cutting plane are arranged rotationally symmetrically around the optical waveguide axis.

[0022] In a further particularly preferred embodiment of the optical waveguide, the micromodifications are arranged on a hollow cone, wherein the longitudinal axis of the hollow cone lies on the optical waveguide axis.

[0023] In another particularly preferred embodiment of the optical waveguide, the micromodifications are arranged on several hollow cones, wherein the hollow cones have different diameters and wherein the longitudinal axes of the hollow cones lie on the optical waveguide axis. The micromodifications do not have to fill the entire area of ​​the cone up to the tip, which includes, among other things, truncated cones or spirals on a cone.

[0024] In a further particularly preferred embodiment of the optical waveguide, the region at the distal end of the optical waveguide is divided into two sections in the direction of the optical waveguide axis, of which a first section faces the distal end of the optical waveguide and a second section faces away from the distal end of the optical waveguide.

[0025] Another particularly preferred embodiment is to divide the processed region of the optical waveguide into at least two sections in which different ordered micromodifications are introduced in different orientations and embodiments.

[0026] The method according to the invention for introducing micromodifications into optical waveguides comprises fixing an optical waveguide in one or more holders, wherein the optical waveguide and / or the holder are movably mounted, focusing high-energy laser radiation with a focusing device into a focus position, wherein the focus position can be positioned inside the optical waveguide, wherein the radiation is generated by a radiation source in pulsed operation, wherein the focusing device for focusing the high-energy radiation is movably mounted, moving the focus position through the optical waveguide, wherein the movement of the focus position inside the optical waveguide is specifically selected as a function of the repetition rate in order to produce a predetermined arrangement of the micromodifications.

[0027] Preferably, the method for introducing micromodifications into optical waveguides comprises moving the optical waveguide in a rotational movement,

[0028] In a preferred embodiment of the method for introducing micromodifications into optical waveguides, the focus position is continuously moved through the optical waveguide.

[0029] In a further preferred embodiment of the method for introducing micromodifications into optical waveguides, the movement of the focus position through the optical waveguide comprises a combination of rotational and one or more translational movements.

[0030] In a further preferred embodiment of the method for introducing micromodifications into optical waveguides, the movement of the focus position is correlated with the repetition rate in such a way that an ordered, uniform or systematically changing arrangement of micromodifications in the optical waveguide is created.

[0031] In a further particularly preferred embodiment of the method for introducing micromodifications into optical waveguides, the arrangement of the micromodifications is described by one or more parameters from a group of parameters comprising the symmetrical arrangement of the micromodifications, the density of the micromodifications on the cutting plane, the size of the micromodifications, the distance of the micromodifications from the optical waveguide axis, the distance of the micromodifications from one another, the orientation of the micromodifications or other parameters with the aid of which the position and distribution of the micromodifications or their size or external shape are described.

[0032] In a further particularly preferred embodiment of the method for introducing micromodifications into optical waveguides, the direction of incidence of the radiation onto the optical waveguide occurs at an angle between the optical waveguide axis and the direction of incidence of not equal to 90°, in a preferred range at an angle of not equal to 90° + / - 5°, in a particularly preferred range at an angle of not equal to 90° + / - 10°.

[0033] In a further particularly preferred embodiment of the method for introducing micromodifications into optical waveguides, the focusing device is additionally set into oscillation in the lateral and transverse directions.

[0034] The method for introducing micromodifications preferably utilizes a laser system capable of generating ultrashort laser pulses. The pulse length is preferably in the range between 0.01 and 1000 ps, ​​more preferably in the range between 0.05 and 10 ps, ​​and most preferably between 50 and 500 fs. The wavelengths used range from the visual to the near infrared range and are preferably between 300 and 1500 nm, more preferably between 500-532 nm or 1000-1064 nm. The range of the individual pulse energies used is preferably between 1 µJ and 100 µJ, more preferably 1 to 50 µJ. This results in power densities between 10 12 and 10 15 W / cm 2 in the focus area.

[0035] The repetition rate used or achievable by the laser system decisively determines the processing speed when introducing micro-modifications into an optical fiber. The higher the repetition rate, the faster the focusing device can be moved while maintaining a constant spacing between the micro-modifications. A high repetition rate is therefore generally preferable. However, it should be noted that the processing axes must be able to move quickly and precisely. Furthermore, very high repetition rates greater than or equal to 1 MHz can lead to heat accumulation within the optical fiber, as the energy introduced into the irradiated volume of the optical fiber can no longer be dissipated quickly enough. This heat accumulation can lead to stress cracks and thus to mechanical instability or even destruction of the optical fiber.Preferably, a repetition rate in the range of 1 kHz to 1 MHz is chosen, particularly preferably 1 and 100 kHz.

[0036] The use of ultrashort light pulses (pulse duration ≤ 10 ps) has the advantage that the influence of the applied heat energy remains very small, enabling the introduction of spatially limited micro-modifications without damaging the surrounding material. If laser pulses in the nanosecond range are used, the energy is transferred to the ion lattice of the irradiated material during a single pulse. This leads, as with an excessively high repetition rate, to heat accumulation in the irradiated material volume and the formation of microscopic stress cracks, whose extent can easily be in the millimeter range. This damage to the material of the optical fiber can lead to a reduction in mechanical stability and even to the possible fracture of the optical fiber under mechanical and / or thermal stress.

[0037] The use of ultrashort laser pulses allows for targeted modification of material properties only in the irradiated area of ​​a few micrometers, without unintentionally damaging surrounding areas. In this case, the pulse duration is insufficient to transfer the energy to the ionic lattice of the surrounding material, resulting in no or significantly reduced heat accumulation. This allows for the creation of very small structures at very low stresses in the surrounding material. Both the smallest possible structures and the lowest possible stresses are necessary conditions for the targeted introduction of micromodifications into optical fibers. This is the only way to achieve targeted structuring of the optical fiber material without compromising its mechanical stability.

[0038] For the method for introducing micromodifications into optical fibers, a device is provided that includes an axis and motor system. This device serves, on the one hand, to hold the optical fiber and, on the other hand, allows the optical fiber to be moved and rotated in a targeted manner, and enables the focus of the laser system to be positioned as desired within the optical fiber. The method according to the invention and the associated device according to the invention allow the shape, distribution, and position of the micromodifications within the optical fiber to be varied as desired. For example, the position or shape of the micromodifications can be specifically influenced by the travel speed of the linear and rotational axes or by varying the repetition rate. The distribution of the micromodifications can also be specifically controlled, e.g., by so-called laser-internal "pulse picking" or a programmable shutter.The depth of the micromodifications relative to the surface of the optical fiber cladding can be influenced by a targeted movement of the focus, through targeted adjustment of the focusing device. Furthermore, the depth extension of the individual micromodifications can also be specifically influenced by appropriate selection of single pulse energy, pulse duration, pulse number (single, double, multiple pulses), spatial and / or temporal spacing, or even by pulse tailoring. It is also possible to introduce micromodifications into the optical fiber on the side facing away from the laser system by focusing through the center of the optical fiber. Here, it is possible to additionally utilize the lens-like effects of the curved surface of the optical fiber for focusing, thus creating micromodifications with an even shorter depth extension. The focus position, or rather, the focal length, can also be adjusted.The positioning of the focusing device relative to the fiber optic axis influences the arrangement of the micromodifications. For example, the alignment of the micromodifications can be controlled by shifting the beam position from the perpendicular to the fiber optic axis.

[0039] Any parameters that can be used to describe the micromodifications, such as the depth position, spatial extent, distribution, spacing, position, orientation, or even shape of the micromodifications, can influence the mechanical stability of the optical fiber. The smaller the spatial extent of the micromodifications and the greater the spacing between them, the smaller the influence on the mechanical stability of the optical fiber. On the other hand, the strength of the light extraction caused by the micromodifications is essentially opposite to the effects on mechanical stability. Therefore, it is essential to find a compromise between the extracted light intensity and the mechanical or thermal stability of the optical fiber.

[0040] Various designs are conceivable with regard to the distribution of the micromodifications. For example, it is possible to create an intentionally irregular distribution of the micromodifications in order to avoid grating effects such as interference and at the same time ensure a uniform distribution of the outcoupled light. On the other hand, a targeted regular or periodic distribution of the micromodifications, such as Bragg gratings or multi-dimensional photonic structures, is also conceivable. Furthermore, it is possible to place the micromodifications inside the optical waveguide so densely that these modifications form a line that itself possesses waveguide properties. This line structure can be of any length and its course relative to the optical waveguide can also be of any design; for example, a straight, spiral, or helical design is conceivable.

[0041] The processing options described are not limited to a specific type of optical fiber. By appropriately adjusting the processing parameters, it is possible to process any type of optical fiber, such as hollow fibers, gradient index fibers, innovative high-tech lead-free glass fibers, photonic crystals, or photonic crystal fibers.

[0042] The invention is explained in more detail below using several exemplary embodiments. They show: Figure 1 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation Figure 2 Schematic representation of an optical waveguide and the coupling of focused laser light as well as the possibilities of relative movement between focused laser light and optical waveguide Figure 3 Schematic structure of the processing device for processing optical waveguides a) Front view b) Side view Figure 4 Method for processing optical waveguides with laser radiation Figure 5 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation a) Optical waveguide b) Cross sections along the cutting lines A - A, B - B, C - C, D - D and E - E Figure 6 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation a) Optical waveguide b) Cross sections along the cutting lines A - A, B - B, C - C,D - D and E - E Figure 7 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation a) Optical waveguide b) Cross sections along the section lines A - A, B - B, C - C, D - D and E - E Figure 8 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation a) - e) Cross sections along the section lines A - A, B - B, C - C, D - D and E - E f) Cross section along the optical waveguide axis Figure 9 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation a) - c) Various periodic sequences Figure 10 Schematic structure of an optical waveguide with micro-modifications induced by laser radiation a) Sequence of cross-sections with different distribution and / or arrangement of micro-modifications b) Periodic sequence of regions with the same sequence of cross-sections with different distribution and / or arrangement of micro-modifications,

[0043] Figur 1 shows a schematic representation of the optical waveguide (1) to be processed. The optical waveguide comprises a first region (15) that is largely free of micromodifications (5), and a second region (16) of the optical waveguide (1) in which micromodifications (5) are introduced. This region (16) is usually arranged at the distal end of the optical waveguide (1). Optionally, the optical waveguide can be provided with an end cap (14) that prevents light from escaping from the end region of the optical waveguide (1). This end cap (14) can, by reflecting the light waves, feed them back to a lateral outcoupling through micromodifications. The end cap (14) can be replaced by a suitable, direct mirroring of the fiber end face, which is also according to the invention. The core (11) is surrounded by the cladding (12), followed by the coating and / or buffer (13). The core (11) and cladding (12) are usually made of quartz and are differently doped.The refractive index of the cladding material is lower than that of the core material, so that the light can be transported by total internal reflection at the core-cladding junction in the optical fiber (1). The cladding (12) is surrounded by a so-called coating and / or buffer (13), which absorbs the stresses when the optical fiber (1) is bent and thus ensures non-destructive flexibility and also serves to protect the underlying layers from mechanical influences. To process the optical fiber (1), the buffer (13), which is opaque for the selected laser wavelength, can be removed so that the laser light only needs to be focused through the cladding (12). If the buffer material is transparent for the selected laser wavelength, e.g. nylon or PTFE, the optical fiber (1) can also be processed through the buffer (13).This has the advantage that the machined area of ​​the optical fiber (1) has essentially the same increased bending strength as the rest of the optical fiber (1).

[0044] In Figur 2 the principle of coupling the focused laser light (2) into the optical waveguide (1) for introducing the micromodifications (5) is also shown. Figur 2 shows the focusing optics (21) required to focus the laser pulses into the core region of the optical fiber (1) and the resulting micromodifications (5). Important lens parameters for incorporating the micromodifications (5) into the optical fiber (1) are the focal length and the numerical aperture (NA) of the symbolically represented focusing optics (21). The focal length is chosen to be as short as possible, as this allows the size of the focal point to be minimized. However, the focal length must be long enough to focus through the optical fiber cladding into the core (11). In a preferred variant, the focal length of the focusing optics (21) is between 1 and 5 mm. However, the use of "long-distance" microscope objectives with a working distance of greater than 5 mm is also a preferred implementation option. A NA of the focusing optics (21) that is as large as possible is also advantageous, as this determines the aperture angle of the focusing optics (21).The larger the aperture angle, the shorter the focal range. This is crucial because it minimizes the depth of the introduced modifications (5). The larger aperture angle leads to greater beam divergence and thus to a rapidly increasing beam diameter in front of and behind the focal point. This reduces the energy density in the areas in front of and behind the focus, thus reducing absorption and the risk of damage outside the focal area.

[0045] In a particularly preferred variant, a short focal length (f < 3.1 mm) aspherical lens with a numerical aperture of NA > 0.68 is used as the focusing optics (21). In a further embodiment, a special objective (lens system) with a high NA is used. This is designed so that the wavefronts of the focused laser radiation (22) have the same radius of curvature as the material surface they impinge upon. This has the advantage that the wavefronts are not distorted when passing through the optical waveguide surface (wavefront distortion), which in turn leads to significantly better focusability in the material of the optical waveguide (1).

[0046] Figur 3 shows a schematic diagram of the device according to the invention for introducing micromodifications into optical fibers (20). The device (20) comprises various motorized adjustment devices (33, 34) for performing a linear movement between the optical fiber (1) and the focus of the focused laser beam (22). The movement is preferably carried out via linear motors (33, 34) in the spatial directions (X, Y, Z). The device (20) also comprises the structure for coupling (23) the laser light (2) into the focusing optics (24). The device (20) also comprises the holder (32) for the optical fiber (1) and the rotation axes (α, β 1 , β 2 , β 3 ) for rotating the same. In contrast to previously known solutions, the focusing lens is not moved, but only the optical fibers (1). This has the advantage that no deflecting mirrors need to be moved or displaced in the beam path during processing. As a result, the furnishing orThe adjustment effort for the device is significantly lower and at the same time the long-term stability of the structure is improved because all optical elements can be permanently installed in the beam path. Even minor inaccuracies or deviations in the beam path would lead to a migration of the laser beam (2) on the focusing optics (24) in the case of, for example, translationally moved deflecting mirrors. As a result, the focal point migrates both in the XY plane and in the Z direction due to the beam passage through the focusing optics (24) being inclined (not perpendicular) relative to the optical fiber (1). A long-term stable structure with reproducible processing results is therefore very difficult or even impossible to achieve.

[0047] The Z-axis (34) carries the further processing structure consisting of the X- and Y-axes (33), rotation device (31), and holder / guide (32) for the optical fiber (1). It is used to move the optical fiber (1) towards or away from the focusing optics (24). In this way, the distance of the focus point from the center of the optical fiber (1), i.e. the depth position, can be varied. The X-axis (33) is used to move the optical fiber or the holder / guide (32) along the optical fiber path under the focusing optics (24). The maximum length of a modified area is therefore determined solely by the maximum travel distance of this axis. The Y-axis (33) moves the holder / guide (32) perpendicular to the optical fiber path under the focusing optics (24).It is used to control the alignment of the micro-modifications (5), as the Y-axis (33) can be used to align the focusing optics (24) and the optical fiber (1) so that the laser beam (2) hits the optical fiber surface as vertically as possible. An oblique impact on the surface leads to a changed beam path with a distortion of the focus area and therefore influences not only the alignment but also the shape and size of the modifications introduced. The laser beam (20) used is usually guided into the focusing optics (24) via a deflecting mirror (23), but this is not mandatory. The optical fiber (1) to be processed is held in a precise position in front of the focusing optics (24) by a holder and guide (32). This guide is recessed in the processing area or is transparent to the laser radiation (2 or 22) used.The rotation device (31) rotates the optical fiber (1) around its longitudinal axis. For this purpose, the optical fiber (1) is secured to the rotation device (31) using a clamping device. To avoid excessive torsional stress on the optical fiber (1), it is rotated step by step by up to 360 degrees and then by up to 360 degrees in the opposite direction. This is feasible for both loose optical fiber sections, e.g., prefabricated optical fibers, and for roll-to-roll manufacturing processes in which the optical fibers (1) can be of any length.

[0048] In Figur 4 In one embodiment of the invention, a method for processing optical waveguides (1) with laser radiation (2) is presented. First, the optical waveguide (1) is fixed in its position (41) with the aid of a holder / guide (32). The holder / guide (32) is designed such that the area of ​​the optical waveguide (1) in which the micro-modifications are to be created is accessible to the laser radiation (2). The optical waveguide is mounted such that it can be moved in three spatial directions relative to the focus position. This can be achieved by a movable optics (24) and rigid mounting of the optical waveguide (1), or by a rigid optics (24) and a movably arranged optical waveguide (1). The movement options include the three spatial directions X, Y, and Z as well as the rotation α about the longitudinal axis of the optical waveguide (1) and / or the rotation β 1 , β 2 , β 3 about one or more axes.In a further method step (42), the laser beam (2) is focused. The focused laser beam (22) is positioned such that the position of the focus can be moved across the entire area in which micromodifications are to be introduced using the movement options. The focus position is moved through the optical fiber according to a predetermined pattern (43). A pulsed laser beam is preferably used. By continuously moving the focus position through the optical fiber (1) at a constant speed, micromodifications (5) are created with an equidistant spacing in the direction of movement. By moving the focus position through the optical fiber (1) according to a predetermined pattern, 20 or more micromodifications (5) are created.In a preferred embodiment of the invention, more than 36 micromodifications (5), particularly preferably more than 360 micromodifications (5), are generated by moving the focus position through the optical waveguide (1) according to a predetermined pattern. In a further method step, the movement of the focus position through the optical waveguide (5) is repeated according to a predetermined pattern (44).

[0049] In a further advantageous embodiment, after completion of the micro-modifications (5) introduced by the movement of the focus position through the optical waveguide (1) according to a predetermined pattern, the focus position relative to the optical waveguide (1) is changed by a translational and / or rotational movement.

[0050] This serves to prevent the micro-modifications (5) which were introduced into the optical waveguide (1) in the repetition step by moving the focus position through the optical waveguide (1) according to a predetermined pattern from being located in the direction of the optical waveguide axis (17) exactly behind the micro-modifications (5) which were introduced into the optical waveguide (1) in the first step by moving the focus position through the optical waveguide (1) according to a predetermined pattern.

[0051] In a further advantageous embodiment of the invention, the continuous movement of the focus position through the optical fiber (1) is carried out along the optical fiber axis, thus subsequently resulting in one of the described arrangements in the cutting plane. Thus, the machining process within several cutting planes is divided into the generation of individual points during each pass along the optical fiber axis (17).

[0052] In a further advantageous embodiment of the invention, the continuous movement of the focal position through the optical waveguide (1) according to a predetermined pattern is superimposed by a further movement. This movement can, for example, be oscillations that serve to create a certain lateral offset between the micromodifications (5) that were introduced into the optical waveguide (1) in the repetition step by the movement of the focal position through the optical waveguide (1) according to a predetermined pattern, and the micromodifications (5) that were introduced into the optical waveguide (1) in the first step by the movement of the focal position through the optical waveguide (1) according to a predetermined pattern. The amplitude of the oscillation is preferably at least half the distance between adjacent micromodifications (5). This creates an ordered arrangement of micromodifications within the meaning of the present invention.

[0053] The micromodifications (5) are arranged in the optical waveguide (1) in such a way that when light is radiated through the optical waveguide along the optical waveguide axis (17), the micromodifications are arranged in such a way that the light is deflected as completely as possible to the side by the micromodifications.

[0054] In a further advantageous embodiment of the invention, the micromodifications (5) are introduced into the optical waveguide (1) by positioning the optical axis (25) of the laser beam (2) away from the optical waveguide axis (17) when irradiating the optical waveguide (1). In the case of micromodifications (5) whose shape deviates significantly from a round shape, i.e. has a more elongated shape, an almost closed surface or line of micromodifications (5) can be achieved simply by a rotational movement.

[0055] In a further advantageous embodiment of the invention, the micromodifications (5) are introduced into the optical waveguide (1) in that the optical axis (25) of the laser beam (2) strikes the optical waveguide (1) at an angle (β 1 , β 2 , β 3 ) which is not equal to 90° when the optical waveguide (1) is irradiated. In the case of micromodifications with an elongated shape, this results in an acute angle between the orientation of the micromodification (5) and the optical waveguide axis (17). In a further embodiment of the invention, the angle (β 1 , β 2 , β 3 ) between the orientation of the micromodification (5) and the optical waveguide axis (17) lies in a range between 10° and 80°, in a preferred embodiment in a range between 20° and 70°, and in a particularly preferred embodiment between 30° and 60°.

[0056] In Figur 5 The schematic structure of an optical waveguide with micromodifications induced by laser radiation (partial image a)) as well as sectional images along the section lines A - A, B - B, C - C, D - D and E - E (partial image b)) is shown. The optical waveguide (1) is made up of a core region (11) and a cladding region (12). By irradiation according to the inventive method (40), micromodifications (5) were introduced into the core region (12) of the optical waveguide (1). The micromodifications (5) on the section planes shown (A - A, B - B, C - C, D - D and E - E) are arranged rotationally symmetrically around the optical waveguide axis (17). The micromodifications (5) are at the same distance from the optical waveguide axis (17) on each section plane and are arranged on a circular arc around the optical waveguide axis (17).In the sectional plane A-A, the micromodifications (5) are located close to the cladding (12) of the optical waveguide (1) and are at a great distance from the optical waveguide axis (17). As the sectional planes B-B to E-E extend, the distance between the micromodifications (5) and the cladding (12) of the optical waveguide (1) increases, and the distance between the micromodifications (5) and the optical waveguide axis (17) decreases. In a further advantageous embodiment of the invention, the number of micromodifications (5) arranged on a circular arc in a sectional plane decreases with the distance between the micromodifications (5) and the optical waveguide axis (17). This is achieved by varying the time interval between two laser pulses and / or varying the rotation speed.

[0057] In a further advantageous embodiment of the invention, the arrangement of the micromodifications takes place in only one of the section planes shown here (e.g. A - A) along the entire optical waveguide or in several circles within each other, ie as arrangements of section planes shown here combined in one section plane (e.g. AA with CC and / or EE),

[0058] Figur 6 shows in partial image a) the schematic structure of an optical waveguide with micromodifications induced by laser radiation. In partial image b) the cross-sections along the section lines A - A, B - B, C - C, D - D and E - E are shown. The optical waveguide (1) is made up of a core region (11) and a cladding region (12). By irradiation with high-energy radiation, micromodifications (5) were introduced into the core region (12) of the optical waveguide (1) according to the inventive method (40). The micromodifications (5) on the section planes shown (A - A, B - B, C - C, D - D and E - E) are arranged rotationally symmetrically about the optical waveguide axis (17). The number and arrangement of the micromodifications (5) are the same in every section plane. The arrangement of the micromodifications (5) on section plane B - B is rotated by an angle around the optical waveguide axis (17) compared to the arrangement of the micromodifications (5) on section plane A - A.This rotation of the arrangements of the micromodifications (5) can be achieved by rotating the optical fiber between the processing intervals for introducing the micromodifications (5) into the optical fiber (1). As the section planes A - A to E - E progress, the angle of rotation of the individual section planes B - B to E - E increases compared to section plane A - A. In a further advantageous embodiment of the invention, the number of section planes A - A to E - E with different rotation angles in a processing interval is selected such that the arrangement of the micromodifications (5) in the last section plane of the processing interval E - E would, upon continuation of the rotation, lead again to the arrangement of the micromodifications (5) on the first section plane A - A of the processing interval.

[0059] In Figur 7 The schematic structure of an optical waveguide with micromodifications induced by laser radiation (partial image a)) as well as sectional images along the section lines A - A, B - B, C - C, D - D and E - E (partial image b)) is shown. The optical waveguide (1) is made up of a core region (11) and a cladding region (12). By irradiation according to the inventive method (40), micromodifications (5) were introduced into the core region (12) of the optical waveguide (1). The micromodifications (5) on the individual section planes (A - A, BB, C - C, D - D and E - E) are arranged rotationally symmetrically around the optical waveguide axis (17). The micromodifications (5) are arranged on circular arcs around the optical waveguide axis (17) on the individual section planes AA to E - E. The radii of the circular arcs change along the section planes A - A to E - E.Furthermore, the arrangement of the micromodifications (5) on a cutting plane B-B is rotated by an angle around the optical waveguide axis (17) compared to the arrangement of the micromodifications (5) on an adjacent cutting plane A-A. To transfer the processing steps for arranging the micromodifications (5) on a cutting plane A-A to the processing steps for arranging the micromodifications (5) on an adjacent cutting plane B-B, a combination of a rotation around the optical waveguide axis (17) and translation of the focused laser beam (22) relative to the optical waveguide (1) between the processing steps for arranging the micromodifications (5) on the adjacent cutting planes is possible.

[0060] In a further advantageous embodiment of the invention, the arrangement of the micromodifications takes place in only one of the sectional planes shown here (e.g. A - A) along the entire optical fiber, but rotated around the optical fiber axis or from a combination of sectional planes, i.e. as arrangements of sectional planes shown here combined in one sectional plane (e.g. AA with CC and / or EE). In a further advantageous embodiment of the invention, the arrangement of the micromodifications takes place in a combination of sectional planes, i.e. as arrangements of sectional planes shown here combined in one sectional plane (e.g. AA with CC and / or EE), which, however, changes with each additional sectional plane according to the described pattern of the individual sectional planes.

[0061] Figur 8 shows, using cross-sectional images with sections perpendicular to the optical waveguide axis (17) (partial images a) to e)) and a longitudinal section along the optical waveguide axis (17) (partial image f)), various embodiments of the invention, in which different configurations of micromodifications (5) are illustrated that were induced in an optical waveguide by laser radiation. Partial images a) and b) show micromodifications (51, 52) of different sizes. The position of the micromodifications can be selected independently. The size of the micromodifications (51, 52) can be influenced by the size of the focus and / or by the amount of introduced energy. The energy for the individual pulse can be between 1 and 50 µJ and the micromodifications become larger with increasing energy, although this depends on the material of the optical waveguide and the laser beam quality.It is also possible to arrange micromodifications (5) so that their interfaces touch or overlap. The shape and positioning of the focus can also influence the shape of the micromodification (52, 53). A very long focus results in micromodifications (53) that have an ellipsoidal cross-section with a high length-to-width ratio, whereas a short focus length results in micromodifications (52) that have a small length-to-width ratio. The shape of the micromodifications (53, 54, 55, 56) is a further parameter that can be used to create an ordered arrangement of the micromodifications (5). Different orientations of the longitudinal direction of the micromodifications (53, 54, 55, 56) are shown in partial images c) to f). In partial image c), the micromodifications (53) are all oriented in the same direction.This is achieved when a lateral translation in the Y direction is carried out between the optical waveguide (1) and the focus position between the laser radiation pulses, and the refraction caused by the focused laser beam (22) impinging obliquely on the surface of the optical waveguide (1) is compensated for by a suitable rotation of the focused laser beam (22) by β 1 , β 2 , β 3 . In partial image d), the orientations of the micromodifications (54) are arranged rotationally symmetrically about the optical waveguide axis (17) of the optical waveguide (1). During processing, this is achieved by rotating the optical waveguide (1) about the optical waveguide axis (17) between the laser pulses. The micromodifications (54) are oriented such that the axis along the longitudinal direction of the micromodification (54) through the center of the micromodification (54) intersects the optical waveguide axis (17) of the optical waveguide (1).Partial image e) shows the arrangement and orientation of the micromodifications (5) when, in addition to the processing method for partial image d), the focused laser radiation (22) is not introduced in the direction of the optical waveguide axis (17), but the optical waveguide (1) is shifted laterally to the optical waveguide axis (17). The micromodifications (55) are then oriented such that an axis along the longitudinal direction of the micromodification (55) does not intersect the optical waveguide axis (17) of the optical waveguide (1). Partial image f) shows micromodifications (56) whose axis along the longitudinal direction of the micromodification (56) forms an acute angle (γ) through the center of the micromodification (56) to the optical waveguide axis (17).The angle (γ) between the orientation of the micromodification (5) and the optical waveguide axis (17) lies in a range between 10° and 80°, in a preferred embodiment in a range between 20° and 70°, and in a particularly preferred embodiment between 30° and 60°. The angle (γ) can be aligned with the tip toward the distal or proximal end of the optical waveguide (1). The arrangement of the micromodifications can be rotationally symmetrical to the optical waveguide axis (17) and become narrower toward the distal and proximal ends of the optical waveguide (1).

[0062] A movement pattern for arranging and / or orienting micromodifications (5, 51, 52, 53, 54, 55, 56) in an optical fiber (1) comprises one or more movements from the group comprising a translation along the spatial directions X, Y and / or Z and / or rotations about the optical fiber axis (17) and / or an axis perpendicular to the optical fiber axis (17). Within a movement pattern, at least one micromodification (5, 51, 52, 53, 54, 55, 56) is generated in the core (11) of the optical fiber (1). Between the first execution of the movement pattern and the second and / or a subsequent repetition of the execution of the movement pattern, one or more movements from the group comprising a translation along the spatial directions X, Y and / or Z and / or rotations about the optical fiber axis (17) and / or a spatial axis take place.The area in which micromodifications (5, 51, 52, 53, 54, 55, 56) were introduced into the optical waveguide (1) in a first movement pattern and the area in which micromodifications (5, 51, 52, 53, 54, 55, 56) were introduced into the optical waveguide (1) in a second movement pattern can overlap.

[0063] Figur 9 shows in partial images a) to c) the schematic structure of an optical waveguide (1) with laser-induced micromodifications (5). The marked cutting lines A, B und C are characteristic of areas in which micromodifications (5) have been introduced into the optical waveguide (1) as a result of a movement pattern of the focus position of the focused laser beam (22) through the optical waveguide (1). Partial image a) shows a sequence of exemplary three different areas ( A, B, C ) of arrangements of micromodifications (5) that are repeated over the length of the optical fiber. The number of repetitions can also be multiple. The areas ( A , B, C ) have different arrangements of the micromodifications. A region (A, B, C) is defined by one or more of the characteristics from the group comprising the size, number, orientation, shape and / or arrangement of the micromodifications (5, 51, 52, 53, 54, 55, 56). The micromodifications (5, 51, 52, 53, 54, 55, 56) of each region (A, B, C ) are induced by a movement pattern of the focus position of the focused laser radiation (22) through the optical waveguide (1) and the associated irradiation. Due to the different arrangements of the micromodifications (5, 51, 52, 53, 54, 55, 56), the arrangements of the micromodifications (5, 51, 52, 53, 54, 55, 56) in the areas ( A, B, C ) are created by different movement patterns. Between the first execution of a movement pattern to create an area ( A, B, C ) one or more of movements of the focus position with respect to the optical waveguide (1) from a group comprising the three spatial directions X, Y, and Z as well as the rotation α about the longitudinal axis of the optical waveguide (1) and the rotation β 1 , β 2 , β 3 about one or more axes.

[0064] In part b) of Figur 9 In a further embodiment of the invention, a further sequence of areas ( A , B, C ) of the same arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56) in an optical waveguide (1). While the first area ( A ) is present once, two areas follow with a second arrangement ( B ) and three areas with a third arrangement ( C). In this processed optical waveguide (1), not all areas with micromodifications (5, 51, 52, 53, 54, 55, 56) arranged according to a specific pattern are present multiple times.

[0065] Part c) of the Figur 9 shows in a further embodiment of the invention another possible sequence of areas ( A, B, C ) same arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56). While the first area ( A ) to each area ( A, B, C ) which is not the same as the first area ( A ), the second and third areas follow ( B, C ) alternating with the first area ( A ) .

[0066] Further embodiments of the invention can be represented by any mathematical series and sequences. In a further embodiment of the invention, an optical waveguide (1) according to the invention comprises more than three regions ( A, B, C ) with different arrangements of micromodifications (5, 51, 52, 53, 54, 55, 56). In a preferred embodiment of the invention, the optical waveguide (1) comprises more than five regions ( A, B, C ), in a particularly preferred embodiment more than ten areas ( A, B, C ) with differently arranged micromodifications (5, 51, 52, 53, 54, 55, 56).

[0067] Figur 10 shows in parts a) and b) the schematic structure of an optical waveguide (1) with micromodifications (5, 51, 52, 53, 54, 55, 56) induced by focused laser radiation (22). Part a) shows a sequence with a large number of areas ( A, B, C, D, E, F, G, H, I, J ) with different arrangements of micromodifications (5, 51, 52, 53, 54, 55, 56). This sequence of areas ( A, B, C, D, E, F, G, H, I, J ) with different arrangements of micromodifications (5, 51, 52, 53, 54, 55, 56) is repeated n times (part b)). n, m are natural numbers. m stands for the number of repetitions of a sequence with a large number of areas ( A, B, C, D, E, F, G H, I, J ) with different arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56).

[0068] In a preferred embodiment of the invention, the number of repetitions of a sequence with a plurality of regions ( A, B, C, D, E, F, G, H, I, J ) with different arrangements of micromodifications (5, 51, 52, 53, 54, 55, 56) greater than five, in a particularly preferred embodiment greater than twenty.

[0069] In a further embodiment of the invention, the arrangement of the repetitions of a sequence with a plurality of areas ( A, B, C, D, E, F , G, H, I, J ) with different arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56) alternating in the orientation of their arrangement.

[0070] In a further embodiment of the invention, the arrangement of the repetitions of a sequence with a plurality of areas ( A, B, C, D, E, F, G, H, I, J ) with different arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56) a mixed form of alternating and co-directional orientation of their arrangement. BEZUGSZEICHENLISTE

[0071] 1 Optical fiber 11 Core of the optical fiber 12 Cladding of the optical fiber 13 Coating, buffer and / or further coatings of the optical fiber 14 End cap 15 Proximal end of the optical fiber 16 Distal end of the optical fiber 17 Optical fiber axis 2 Laser beam 20 Device for introducing micro-modifications into optical fibers 21 Symbolized focusing optics 22 Focused laser beam 23 Deflecting mirror 24 Focusing optics 25 Optical axis 31 Rotation device 32 Holder / guide for the optical fiber 33 Lateral positioning device 34 Vertical positioning device α Rotation of the optical fiber around the optical fiber axis β 1 , β 2 ,β 3 Rotation of the direction of incidence of the laser beam 40Procedure for introducing micromodifications into optical fibers 41Fixing the optical fiber in a holder 42Focusing laser radiation in a focal position 43Moving the focal position through the optical fiber according to a predetermined pattern 44Repeating one of the movements of the focal position through the optical fiber according to a predetermined pattern 5, 51, 52, 53,Micromodification 54, 55, 56, γAngle of the longitudinal alignment of the micromodifications to the optical fiber axis A, B, C, D, ERadial section planes through the optical fiber, can also be inclined FAxial section plane through the optical fiber , A, B, C, D, Areas of the optical fiber with arranged E, F, G, H, JMicromodifications mNumber of repetitions of a sequence with a large number of areas with different arrangement of micromodifications nmaximum number of repetitions of a sequence with a large number of areas with different arrangement of micromodifications

[0072] Example 1: Optical fiber comprising a light wave-guiding core, a region in the optical waveguide, wherein micromodifications are arranged in the region of the optical waveguide, wherein the arrangement of the micromodifications is ordered.

[0073] Example 2: Optical fiber according to Example 1, characterized in that the micromodifications are arranged on one or more cutting planes, wherein the cutting planes are substantially perpendicular to the optical waveguide axis, and wherein the arrangement of the micromodifications on the cutting plane is defined by one or more parameters from a group of parameters comprising the symmetrical arrangement of the micromodifications, the density of the micromodifications on the cutting plane, the size of the micromodifications, the distance of the micromodifications from the optical waveguide axis, the distance of the micromodifications from one another, the orientation of the micromodifications, or other parameters used to describe the position and distribution of the micromodifications or their size or external shape.

[0074] Example 3: Optical waveguide according to example 1 or 2, characterized in that the arrangement of the micromodifications on a first cutting plane is repeated on at least one other cutting plane.

[0075] Example 4: Optical waveguide according to Example 3, characterized in that the cutting plane on which the arrangement of the micromodifications on the first cutting plane is repeated is rotated by an angle relative to the first cutting plane.

[0076] Example 5: Optical waveguide according to Example 3, characterized in that the distance between the first cutting plane and the other cutting plane on which the arrangement of the micromodifications is repeated is greater than the extent of a micromodification.

[0077] Example 6: Optical waveguide according to one of examples 3 or 4, characterized in that between the first cutting plane and the cutting plane on which the arrangement of the micromodifications of the first cutting plane is repeated, there is at least one further cutting plane with micromodifications which has a different arrangement than the first cutting plane.

[0078] Example 7: Optical waveguide according to one or more of Examples 2 to 6, characterized in that the micromodifications on the cutting plane are arranged rotationally symmetrically around the optical waveguide axis.

[0079] Example 8: Optical waveguide according to one or more of Examples 2 to 6, characterized in that the micromodifications are arranged on a hollow cone, wherein the longitudinal axis of the hollow cone lies on the optical waveguide axis.

[0080] Example 9: Optical waveguide according to one or more of Examples 2 to 6, characterized in that the micromodifications are arranged on several hollow cones, wherein the hollow cones have different diameters and wherein the longitudinal axes of the hollow cones lie on the optical fiber axis.

[0081] Example 10: Optical waveguide according to one or more of the preceding examples, characterized in that the region in the optical waveguide in which micromodifications are arranged is divided into at least two sections in the direction of the optical waveguide axis,

[0082] in which different orientations and embodiments of ordered micromodifications are introduced.

[0083] Example 11: Method for introducing micromodifications into optical waveguides comprising Fixing an optical waveguide in a holder, wherein the optical waveguide and / or the holder are movably mounted, focusing high-energy radiation into a focus position, wherein the focus position can be positioned inside the optical waveguide, wherein the radiation is generated by a radiation source in pulsed operation, wherein the focusing device for focusing the high-energy radiation is movably mounted, moving the focus position through the optical waveguide, characterized in that the movement of the focus position inside the optical waveguide is selected as a function of the repetition rate.

[0084] Example 12: Method for introducing micromodifications into optical waveguides according to Example 11, characterized in that the movement of the optical waveguide is carried out in a rotational movement.

[0085] Example 13: Method for introducing micromodifications into optical waveguides according to example 11 or 12, characterized in that the focus position is continuously moved through the optical waveguide.

[0086] Example 14: Method for introducing micromodifications into optical waveguides according to one or more of Examples 11 to 13, characterized in that the movement of the focus position through the optical waveguide is a combination of rotational and translational movement.

[0087] Example 15: Method for introducing micromodifications into optical waveguides according to one or more of Examples 11 to 14, characterized in that the positioning of the focus position in the optical fiber correlates with the repetition rate in such a way that an ordered arrangement of micromodifications in the optical fiber is created.

[0088] Example 16: Method for introducing micromodifications into optical waveguides according to Example 15, characterized in that the arrangement of the micromodifications on the cutting plane by one or more parameters from a group of parameters comprising the symmetrical arrangement of the micromodifications, the density of the micromodifications on the cutting plane, the size of the micromodifications, the distance of the micromodifications to the optical fiber axis, the distance of the micromodifications to one another, the orientation of the micromodifications or other parameters with the help of which the position and distribution of the micromodifications or their size or external shape is described.

[0089] Example 17: Method for introducing micromodifications into optical waveguides according to one or more of Examples 11 to 16, characterized in that the direction of incidence of the radiation onto the optical waveguide is at an angle between the optical waveguide axis and the direction of incidence of not equal to 90°, in a preferred range at an angle of not equal to 90° + / - 5°, in a particularly preferred range at an angle of not equal to 90° + / - 10°.

[0090] Example 18: Method for introducing micromodifications into optical waveguides according to one or more of Examples 11 to 17, characterized in that the focusing device is additionally set into oscillation in the lateral and transverse directions.

Claims

1. Optical waveguide (1) comprising - a light-wave-guiding core (11), - a region (15) in the optical waveguide (1), wherein micromodifications (5, 51, 52, 53, 54, 55, 56) are arranged in the region of the optical waveguide (1).

2. Optical waveguide according to claim 1, wherein the arrangement of the micromodifications (5) is ordered.

3. Optical waveguide according to one or more of claims 1 to 2, wherein the micromodifications (5) comprise an irregular distribution of the micromodifications (5).

4. Optical waveguide according to one or more of claims 1 to 3, wherein cutting planes (AA, BB, CC, DD, EE) are substantially perpendicular to an optical waveguide axis (17) and the micromodifications on each of the cutting planes (AA, BB, CC, DD, EE) are arranged such that the micromodifications have at least two different distances from the optical waveguide axis.

5. Optical waveguide according to claim 4, wherein the cutting planes are arranged such that the micromodifications are arranged spirally along the optical waveguide axis (17).

6. Optical waveguide according to one or more of claims 4 to 5, wherein a distance between the micromodifications on at least one cutting plane is varied compared to a subsequent cutting plane.

7. Optical waveguide according to one or more of claims 1 to 6, wherein the arrangement of the micromodifications on a first sectional plane is repeated on at least one other sectional plane, and / or a number and arrangement of the micromodifications (5) are the same in each sectional plane.

8. Optical waveguide according to claim 7, wherein the sectional plane on which the arrangement of the micromodifications on the first sectional plane is repeated is rotated by an angle relative to the first sectional plane.

9. Optical waveguide according to claim 7, wherein the distance between the first cutting plane and the other cutting plane on which the arrangement of the micromodifications is repeated is greater than the extent of a micromodification.

10. Optical waveguide according to one of claims 7 to 9, wherein between the first sectional plane and the sectional plane on which the arrangement of the micromodifications of the first sectional plane is repeated, there is at least one further sectional plane with micromodifications which has a different arrangement than the first sectional plane; or a sequence of m regions (A, B, C, D, E, F, G, H, I, J ) with different arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56) is repeated n times, where n and m are natural numbers.

11. A method for introducing micromodifications (5, 51, 52, 53, 54, 55, 56) into an optical waveguide (1), the method comprising: fixing the optical waveguide (1) in a holder (32), wherein the optical waveguide (1) and / or the holder (32) is movably mounted; focusing high-energy laser radiation (22) by means of a focusing device (24) onto a focal position, wherein the focal position is positionable inside the optical waveguide (1) and wherein the high-energy radiation (22) is generated by a laser beam source (21) in pulsed operation; wherein a linear relative movement between the optical waveguide (1) and the focal position occurs exclusively through a movement of the optical waveguide (1);and movement of the focus position through the interior of the optical waveguide (1) occurs by the movement of the optical waveguide (1) with a rotation of the optical waveguide (1), and the speed of the rotation is only changed by the movement of the optical waveguide (1) during the movement.; 12. The method according to claim 11, wherein the movement of the focus position through the interior of the optical waveguide (1) is selected as a function of a repetition rate.

13. Method according to one of claims 11 or 12, wherein the focus position is moved continuously through the optical waveguide (1).

14. Method according to one of claims 12 or 13, wherein the movement of the focus position through the optical waveguide (1) is a combination of rotational movement (β2) and translational movement (Z).

15. A device for introducing micromodifications (5, 51, 52, 53, 54, 55, 56) into an optical waveguide (1), comprising: a focusing device (24) for focusing pulsed laser radiation (22) into the interior of the optical waveguide (1); at least one motor-driven positioning device (31, 33, 34) for a linear movement of the focus position relative to the optical waveguide (1), wherein the movement occurs exclusively through movement of the optical waveguide (1); a holder or guide (32) for the optical waveguide (1); a rotation device (20) for rotating the optical waveguide (1); and wherein the device is designed such that the focus position is moved through the interior of the optical waveguide (1) by means of the motor-driven positioning device, while a rotational speed of the movement of the optical waveguide (1) is changed exclusively through its movement.

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